Diversity of oat crown rust (Puccinia coronata f.sp. avenae) isolates detected by virulence and AFLP analyses

Forty Puccinia coronata f.sp. avenae isolates from several European countries and Israel were tested for virulence to 18 differential oat lines. Amplified Fragment Length Polymorphism (AFLP) analysis was used to evaluate the diversity among the studied isolates. Twenty-nine different pathotypes were identified. The prevailing occurrence of pathotypes with a limited number of virulence genes may indicate that oat cultivars grown in Europe possess a limited number of resistance genes. A total of 501 AFLP polymorphic fragments were scored in the studied isolates using twelve primer combinations. All isolates had a unique AFLP molecular pattern. The genetic similarity of isolates from Serbia, Austria and from the Czech Republic indicates that oat crown rust urediniospores may often migrate to particular areas. The number of virulence genes in isolates also seems to play an important role in the clustering. Most isolates possessing a lower number of virulence genes (0-4) were grouped into two clusters, whereas another cluster was composed of a majority of isolates with 4-7 virulence genes. A significant correlation relationship of 0.187 was found between AFLP and virulence/avirulence genes based on distance matrices.